What is the role of glucagon in the body?

Glucagon plays a vital role in maintaining blood glucose levels, particularly when they are low. It is a hormone produced by the alpha cells in the pancreas. When the body's blood sugar levels decrease, glucagon is released into the bloodstream. It functions primarily by stimulating the liver to convert stored glycogen into glucose, which is then released into the blood. This mechanism ensures that cells have a sufficient supply of glucose for energy, especially critical during fasting or between meals.

Additionally, glucagon can promote gluconeogenesis, the process of generating glucose from non-carbohydrate sources, further contributing to raising blood glucose levels. This counter-regulatory action is essential for preventing hypoglycemia and maintaining homeostasis. In contrast, the other options do not relate to glucagon's primary function. For instance, the stimulation of milk production and the inhibition of prolactin are associated with other hormones, and glucagon does not influence blood pressure directly.